I think those are actually eBay affiliates who are hoping for a click and an association with a new account. eBay then pays the affiliate who got you there first a tidy percentage of your spendings with the site as a whole. Those affiliates sure are clever (though I'm forced to question whether this ever works).

Imagine eating up words like Batman and Spiderman back in the day. Not only did this work, it was magic. Once you had "the numbers" in check it was like "putting in a quarter and getting two back."
Too bad it has been ruined by spammers and the natural development of the market.